The present invention relates generally to improvements in air conditioning systems and it relates more particularly to an improved air conditioning system of the type employing a refridgeration unit, external ambient air and recirculated air.
In the air conditioning cooling of internal spaces such as buildings and other structures of a commercial, industrial or domestic nature, it is conventional to employ a heat pump or air conditioning unit and recirculate the internal air past the air conditioning unit cooling by means of a blower and suitably positioned return and supply ducts. The air conditioning unit is actuated and deactuated in response to the internal temperature so as to operate whenever such temperature exceeds an adjustable preset value. The air conditioning unit is a highly energy-consuming device so that its operation is very expensive and any expedient employed in reducing the operating time of the air conditioning unit is highly desirable in that it reduces the operating costs. One such expedient which has been heretofore proposed depends on the use of the ambient atmospheric air when it is sufficiently cool to assist in the cooling of the internal space by drawing the air from the ambient atmosphere and circulating it through the internal space, while dampering off return air. Built up space pressure must then be relieved by a separate control device. While this expedient contributes to a significant reduction in energy consumption, the apparatus required is highly complex, bulky, expensive, often unfeasible, and otherwise leaves much to be desired.